The present invention relates to a detection device, a sensor, and an electronic instrument.
A gyrosensor for detecting a physical quantity which changes due to external factors is incorporated in electronic instruments such as a digital camera, a video camera, a portable telephone, and a car navigation system. The gyrosensor detects a physical quantity such as an angular velocity, and is used for image blur correction, position control, GPS autonomous navigation, and the like.
In recent years, a piezoelectric vibrating gyrosensor has attracted attention as one type of gyrosensor. In particular, a crystal piezoelectric vibrating gyrosensor using a crystal as the piezoelectric material is expected to be a sensor optimum for incorporation into many devices. A detection device of such a vibrating gyrosensor detects a desired signal which is a signal corresponding to the Coriolis force which occurs due to the rotation of the gyrosensor to determine the angular velocity (e.g., JP-A-3-226620).
In such a vibrating gyrosensor, the level of a gyrosensor detection signal (detection current) from a vibrator has become very weak due to a reduction in weight and size of the vibrator. Therefore, a detection device of a vibrating gyrosensor has been required to exhibit more improved signal-to-noise ratio (SNR) performance. However, it is difficult to satisfy such a demand using a normal operational amplifier. When a vibrating gyrosensor is incorporated in an electronic instrument (e.g., portable telephone) for which a reduction in power consumption is demanded, it is desirable to reduce the power consumption of a detection device of the vibrating gyrosensor.